内容简介
#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> int mknod(const char *pathname, mode_t mode, dev_t dev) |
描述
The system call%uA0mknod() creates a filesystem node (file, device special file or named pipe) named%uA0pathname, with attributes specified by%uA0mode%uA0and%uA0dev.The%uA0mode%uA0argument specifies both the permissions to use and the type of node to be created. It should be a combination (using bitwise OR) of one of the file types listed below and the permissions for the new node.
The permissions are modified by the process’s%uA0umask%uA0in the usual way: the permissions of the created node are%uA0(mode & ~umask).
The file type must be one of%uA0S_IFREG,%uA0S_IFCHR,%uA0S_IFBLK,%uA0S_IFIFO%uA0or%uA0S_IFSOCK%uA0to specify a normal file (which will be created empty), character special file, block special file, FIFO (named pipe), or Unix domain socket, respectively. (Zero file type is equivalent to type S_IFREG.)
If the file type is%uA0S_IFCHR%uA0or%uA0S_IFBLK%uA0then%uA0dev%uA0specifies the major and minor numbers of the newly created device special file otherwise it is ignored.
If%uA0pathname%uA0already exists, or is a symbolic link, this call fails with an EEXIST error.
The newly created node will be owned by the effective user ID of the process. If the directory containing the node has the set-group-ID bit set, or if the filesystem is mounted with BSD group semantics, the new node will inherit the group ownership from its parent directory otherwise it will be owned by the effective group ID of the process.
返回值
mknod() returns zero on success, or -1 if an error occurred (in which case,%uA0errno%uA0is set appropriately).错误
| 标签 | 描述 |
|---|---|
| EACCES | The parent directory does not allow write permission to the process, or one of the directories in the path prefix of%uA0pathnamedid not allow search permission. (See also%uA0path_resolution(2).) |
| EEXIST | pathname%uA0already exists. |
| EFAULT | pathname%uA0points outside your accessible address space. |
| EINVAL | mode%uA0requested creation of something other than a normal file, device special file, FIFO or socket. |
| ELOOP | Too many symbolic links were encountered in resolvingpathname. |
| ENAMETOOLONG | |
| %uA0 | pathname%uA0was too long. |
| ENOENT | A directory component in%uA0pathname%uA0does not exist or is a dangling symbolic link. |
| ENOMEM | Insufficient kernel memory was available. |
| ENOSPC | The device containing%uA0pathname%uA0has no room for the new node. |
| ENOTDIR | |
| %uA0 | A component used as a directory in%uA0pathname%uA0is not, in fact, a directory. |
| EPERM | mode%uA0requested creation of something other than a regular file, FIFO (named pipe), or Unix domain socket, and the caller is not privileged (Linux: does not have the%uA0CAP_MKNODꃊpability) also returned if the filesystem containing%uA0pathname%uA0does not support the type of node requested. |
| EROFS | pathname%uA0refers to a file on a read-only filesystem. |
遵循于
SVr4, 4.4BSD, POSIX.1-2001 (but see below).注意
POSIX.1-2001 says: "The only portable use of%uA0mknod() is to create a FIFO-special file. Ifmode%uA0is not S_IFIFO or%uA0dev%uA0is not 0, the behavior of%uA0mknod() is unspecified."Under Linux, this call cannot be used to create directories. One should make directories with%uA0mkdir(2), and FIFOs with%uA0mkfifo(2).
There are many infelicities in the protocol underlying NFS. Some of these affect%uA0mknod().
另请参阅
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